In manufacture of an electronic device, plasma etching is typically used for vertical anisotropic etching with respect to an etching target layer of a workpiece. The plasma etching is also used for etching of a magnetic layer included in a magnetic random access memory (MRAM), that is, a layer that is formed from a magnetic material. The magnetic material is a material that is hardly etched, and various researches have been made with respect to a processing gas for the plasma etching of the magnetic material. For example, Japanese Patent Application Laid-Open Publication No. 2005-42143 discloses plasma etching of a magnetic layer by using a processing gas that contains alcohol. Specifically, Japanese Patent Application Laid-Open Publication No. 2005-42143 discloses plasma etching of the magnetic layer by using a processing gas that contains isopropyl alcohol.
In the plasma etching of the magnetic layer by using the processing gas that contains isopropyl alcohol, a deposit including carbon that is derived from isopropyl alcohol excessively adheres to a surface of a workpiece, which inhibits vertical anisotropy in etching of the magnetic layer. Therefore, Japanese Patent Application Laid-Open Publication No. 2005-42143 discloses a configuration in which a gas such as an oxygen gas and H2O which include an oxygen atom is added to the processing gas to remove the deposit.